The demand for removable magnetic cartridge data storage devices with larger and larger capacities and higher transfer rates continues to grow with the capacity of other forms of data storage such as the hard disk drive (HDD). Industrywide, HDD capacity has grown an average of 60 percent per year since 1991. Software applications, particularly those using audio and video, continue to drive the increasing demand for greater storage capacity. Video is the major capacity driver for the HDD industry today.
In the future, the Internet is expected to play an increasing role in the growth of multimedia applications that require large HDD capacities. Today, most Web sites employ text and static graphics to exhibit their content. But, as the use of broadband communication technologies such as integrated services digital network (ISDN), asymmetric digital subscriber line (ADSL), and cable modems increases, the use of bandwidth-intensive audio/video technologies on the Internet will also increase. This greater Internet access will, in turn, stimulate the development of new graphics applications and programs that will generate additional demand for HDD capacity.
Examples of the kinds of applications that are expected to grow in popularity and further push the requirements of removable cartridge data capacity envelope are:
E-commerce—The online shopping experience will include greater use of audio and video (including 3D video) content. For example, new car shoppers will be able to view full-motion audio/video (AV) files that will provide a fairly accurate idea of an automobile's performance characteristics under different driving conditions. The AV file will be downloadable for later viewing and comparison with other automobile files. Similarly, future mall shoppers will be able to browse virtual shopping centers and digitally “handle” the virtual merchandise by picking 3D objects and manipulating them on their computer screens. For example, furniture shoppers might furnish virtual rooms in their homes by viewing them in 3D perspective.
Photo/Video/Audio Libraries—With the advent of digital cameras and camcorders with digital audio capabilities, PC users can use their HDDs as virtual libraries of photos and videos. The resulting storage requirement will be extensive. With compression, 1,000 reasonably high-resolution images can be stored in 1 GB of disk space. Good-quality compressed video such as Video Home System (VHS) or Moving Picture Experts Group level 1 (MPEG-1) requires about 1.5 Mbps, or about 5.5 gigabits per hour (Gb/hr). High-Definition Television (HDTV) or the equivalent MPEG-2 will increase required storage to approximately 10 Gb/hr.
AV e-mail—Unlike today's primarily text-only e-mail, most e-mail messages will be able to support full-motion video and audio content. Many of these large-capacity messages will be downloaded to the HDD for later action. Depending on file length and file compression level, AV e-mail files will typically range in size from 2 MB to 15 MB or greater.
Education—As more universities and other professional educational institutions offer online programs, multimedia applications will become widespread. Media clips will be included in material sent to students to be downloaded for individual study, and medical doctors will receive surgical updates on new procedures in full-color video and audio.
Corporate Communications and Training—Currently, these applications are primarily intranet in nature, and include such activities as employee communications, executive updates, training modules, and so forth. Content is generally text and static graphic images. However, as streaming media technology improves, AV modules will be sent over the company network and downloaded to the user's HDD for later study at the user's convenience.
The magnetic recording layer on removable magnetic data storage drives has been what is termed “sputtered thin film magnetic media”. This has been the principal rigid platter media type for approximately the past 25 years. Prior to its invention oxide and plated media were the state of the art for rigid disk based magnetic recording devices.
Prior art sputtered thin film magnetic media is typically coated with multiple layers. Most disks are aluminum or glass, plated with a nickel-phosphorous layer, followed by chrome or chrome alloy. The chrome layer is followed by the magnetic layer, usually a cobalt alloy, which is capped by a topcoat, a layer to provide protection against corrosion and wear from the head. A lubricant is finally applied to the disk to further reduce friction between the head and disk.
Companies such as Iomega Corporation have previously built and brought to market removable cartridge recording devices incorporating rigid magnetic media incorporating sputtered thin film magnetic recording layers. The Iomega Jaz 1 GB and Jaz 2 GB are two examples of such products. To accommodate the demand for greater storage capacity, a removable magnetic data storage cartridge having much greater storage and areal densities is needed.